The cases were filed in Washington DC for a total value in damages of $30m (£18.5m).

They were filed by the relatives of student Ragihar Manoharan, Premas Anandarajah – a humanitarian aid worker for Action Against Hunger, and T Thavaraja, the newspaper said.

According to the Daily Mirror, the cases are linked to deaths dating from 2006. Ragihar, the newspaper says, was one of the five students allegedly killed in January 2006 while Anandarajah was one of the 17 Action Against Hunger staff members killed in June 2006.

The Sri Lankan government has repeatedly argued that it has been unfairly criticised for ending a conflict that claimed tens of thousands of lives amid regular suicide bombings of government targets.